This Cronus bug suddenly started happening to me too. The solution is Melodyne Editor. 

I just had to put my two cents into this...  I am a professional recording artist and producer and I used to use Sonar exclusively to make music and compose for film.  I am a member of BMI and the Recording Academy.  The bottom line is Cakewalks Tech Support sucks.  I had the exact same problem with Sonar 8.5 and V-Vocal and it happened suddenly probably after some sort of Windows update.  CWTS told me to un-install everything and clean the registry which I did more than once and still nothing fixed the problem.  I don't have any more time to mess around with this kind of crap.  I have had more down time than productive time and I blame it on Cakewalk.  Their Tech Support also makes you log back into the site to post a response to the help already given.  (That's CRAP!) I should just be able to reply to the email.   

V-Vocal has always been buggy and the bottom line here is that Cakewalk does need to be held accountable for the flaws in their programming.  Because I have been a faithful Sonar user since version 4 and have upgraded every time I expect that they would really support their product and would have fixed this glitch.  I kept hoping that the next version would "fix" the issues.  They never have.  So because they have neglected their customers and put together work-arounds instead of solutions and or patches to their software I quit using Sonar three weeks ago.  I will never return to Cakewalk.  They have lost me as a customer forever.  I have also stopped using Windows OS because for some reason manufacturer's will not keep up with windows updates.  Drivers stop working, programs stop working or develop glitches every time Windows updates.  I was the last hold out of all my musical peers being a PC user.  Funny thing is...these problems rarely if ever happen with a MAC.  All the drivers and programs work all the time.  You just go in and turn the stuff on and be creative.  On the PC, you turn it on and hope windows doesnt need to update and then pray to God if it does that every thing still works afterwards.
I bought a MAC three weeks ago and started using LOGIC Pro.  IMO It's not as cool as Sonar graphically and it's not as user intuitive.  Logic is difficult at first, there are lots of parameters and it's not set up the same, but it does everything Sonar does and more.  In addition it works without glitches and LOGIC supports all third party software un-conditionally as well as supporting external hardware.  Most plug-ins were developed with Mac first so go figure.  The MAC also runs 32 bit and 64 bit plug-ins side by side without any issues.  No bridge required because of the new MAC OS.

Basically...I'm done with Cakewalk, done with Windows...I'm out.  It is un-acceptable for Cakewalk to ignore the problems especially after we spend thousands of dollars on their upgrades.  My advice to everyone...get a mac and go to ProTools or Logic.  Yes it's a little pricey to start over...but it's doable.  

As others have stated, the only true workaround is fix clip >bounce> delete original vvocalclip out of your project.  I have soooo many times accidentially left a small Vvocal clip somewhere hidden, muted in a folder and it crashed my project after days of working on it with no issues.  It is totally unpredictable.

I am just swinging through to voice my frustration with Vvocal crashes as well.  It is such a great tool, I hate to have to go buy melodyne when I already own something that can do the job...minus the crashing.

I can't get beyond Create V-Vocal Clip without Sonar crashing. I did the right thing and contacted CakeWalk Technical Support via the appropriate link, but for over a week now they have studiously avoided responding. Come on Tech Support, you are not doing yourselves any favours. How do I fix this?

Seth Kellogg [Cakewalk
]

Hey Guys,

I edited out correspondence from one of our Technical Support representatives. Please note that Technical Support is for registered customers of our products. We do not allow public disclosure of our help as there is numerous users on this forum and who frequent it that do not have legitimate copies.

If you have any questions about this policy feel free to send me a Private Message.

Best,

Seth, I contacted Tech Support two weeks ago via the appropriate link but so far they haven't responded. I can't get beyond Create V-Vocal Clip without Sonar crashing on me. Some help in resolving this issue would be appreciated, I am a registered customer.

Hey Bluesmeister, coincidentally while working on a new project (after my previous post) I found myself in the same boat as you.  Instant crash when I create a v-vocal clip.  I tried the suggestion on the first post in this thread and it worked for me long enough to creat 1 clip.  Then it reverted back to it's instant crashing nonsense.

I have no advice, just sympathizing with you.
-Mike
Another bump for this thread I guess.  Hopefully the next version will have this smoothed out.

LPMike, I appreciate the sympathy.

Because Seth edited out the procedure in those earlier posts, so it's apparent that Tech Support have a work-around for this problem. I will contact them again...

-Frank

I contacted Tech Support again today (July 4, 2010), I will continue doing so until I get a response.

Hey BluesMeister-
    I forgot to add to my post.  The one project I had that would not allow me to open a VVocal clip, I ended up taking the wave file that needed some fixing and importing it into a new empty project.  I was then able to edit/bounce and then import the new fixed and polished clip back into the original project.  
    This obviously only works if you have 1 project that is immediately crashing when you open V-Vocal but you are able to use it in an empty project. 
-Mike

Mike, I tried V-Vocal in another project that only has one WAV file in it. I split the clip and applied V-Vocal and got the same result... kerrash. Next I will try opening an empty project and recording some guitar and apply V-Vocal to that.

-Frank-